(1.中南大学 粉末冶金国家重点实验室,长沙 410083;
2.中南大学 应用数学与应用软件系,长沙 410083;
3.北京科技大学 材料科学与工程学院,北京 100083)
摘 要: 从宏观的角度出发,仅考虑脱脂预成形坯的体积、粘结剂含量对脱脂过程的影响,将预成形坯几何形状等其他因素的影响合理地归结到扩散系数函数中。根据浓度扩散原理建立了描述粉末注射成形溶剂脱脂过程中预成形坯粘结剂含量随时间变化的数学模型,避免了求解用Fick第二定律描述的偏微分方程,得出了一种预测脱脂量与脱脂时间的有效方法。根据模型求出了脱脂速度函数,给出了一种控制溶剂脱脂过程产生缺陷的分段升温优化方法。用该模型对硬质合金注射成形溶剂脱脂过程进行了模拟和预测,预测结果与实验结果吻合较好。
关键字: 注射成形; 化学溶剂脱脂; 数学模型
(1. State Key Laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China;
2. Department of Applied Mathematics and Applied Software,
Central South University, Changsha 410083, China;
3. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China)
Abstract:A mathematical model of solvent extraction debinding process for powder injection molding is established. An effective method, which can be used to forecast the debinding time for a certain binder loss ratio and binder loss ratio in any debinding time, is given. Based on the equations, a step-by-step heating processing is suggested to avoid debinding defects. The model is used to the simulation of debinding process of the cemented carbide powder compacts and the theoretical prediction tallies with the experimental result quite well.
Key words: powder injection molding; solvent extraction debinding; mathematical model